In May 2009 Cisco announced the Cisco Catalyst 4500 Supervisor Engine 6L-E (Figure 1), optimized for high-performance enterprise access. With the introduction of Cisco IOS Software Release 12.2(53)SG, Supervisor 6L-E is now supported in a mainline release that will also be a long-term maintenance release. Supervisor Engine 6L-E enhances the Cisco Catalyst 4500 E-Series by facilitating performance, enabling services, and protecting investments for enterprises and small and medium-sized businesses (SMBs) deploying business-critical applications. The competitive pricing on the supervisor engine makes it an ideal entry-point offering.

• Advanced quality of service (QoS) support with eight queues per port, dynamic queue sizing, and hierarchical policing

• FAT file system for easier network administration

• Dual 10 Gigabit Ethernet uplinks (X2 optics)

The Cisco Catalyst 4500 E-Series offers services essential for business-critical real-time applications. The Cisco Catalyst 4500 E-Series is easy to manage with features such as Smartports, EEM, and SMARTCallHome. These features combined with standard Cisco Catalyst 4500 features such as QoS, multicast, IPv6, and security features including L2 security, IEEE 802.1X, and Control Plane Policing (CoPP) make it an ideal platform for enterprise access.

Power consumption on the Supervisor Engine 6L-E is optimized, and the supervisor engine shows a 70 percent decline in power consumed/Gbps when compared with the WS-X4013+. The supervisor engine also allows the Cisco Catalyst 4500 chassis to minimize power usage by automatically sensing unused slots and turning off power to the ASICs on unused slots. When combined with Cisco Catalyst 4500 line cards, the system supports Power over Ethernet (PoE), Cisco enhanced PoE, and premium PoE features such as 30W per port.

The Supervisor Engine 6L-E offers flexibility and investment protection. It supports Cisco Catalyst 4500 E-Series line cards in addition to all currently shipping classic Cisco IOS Software supervisor engines, classic line cards dating back to 1999. Classic and E-Series line cards can be mixed and matched with no performance degradation. Twin Gigabit Ethernet converter modules offer flexibility for up to four Gigabit Ethernet Small Form-Factor Pluggable (SFP) uplinks in the X2 optic slots, allowing a phased migration to 10 Gigabit Ethernet. The Supervisor Engine 6L-E works with the 7-slot, 6- slot, and 3-slot E-series chassis and all shipping Cisco Catalyst 4500 power supplies.

OSPF for routed access is designed specifically to enable customers to extend Layer 3 routing capabilities to the access or wiring closet.

Note: OSPF for routed access supports only one OSPFv2 and one OSPFv3 instance with a maximum number of 200 dynamically learned routes.

With the typical topology (hub and spoke) in a campus environment, where the wiring closets (spokes) are connected to the distribution switch (hub) forwarding all nonlocal traffic to the distribution layer, the wiring closet switch need not hold a complete routing table. A best practice design, where the distribution switch sends a default route to the wiring closet switch to reach interarea and external routes (OSPF stub or totally stubby areas configuration), should be used when OSPF for routed access is used in the wiring closet.

If two or more equal-cost paths from a source are available, unicast traffic will be load split across those paths. However, by default, multicast traffic is not load split across multiple equal-cost paths. In general, multicast traffic flows down from the reverse path forwarding (RPF) neighbor. According to PIM specifications, this neighbor must have the highest IP address if more than one neighbor has the same metric. (See Figure 2.)

In Figure 2, two sources, S1 and S2, are sending traffic to IPv4 multicast groups, G1 and G2. Without further configuration, IPv4 multicast traffic in the topology illustrated in Figure 2 would always flow across one serial interface (either serial interface 0 or serial interface 1), depending on which interface has the higher IP address.

Configuring load splitting with the ip multicast multipath command causes the system to load split multicast traffic across multiple equal-cost paths based on source address using the S-hash algorithm. When the ip multicast multipath command is configured and multiple equal-cost paths exist, the path in which multicast traffic will travel is selected based on the source IP address. Multicast traffic from different sources will be load split across the different equal-cost paths. Load splitting will not occur across equal-cost paths for multicast traffic from the same source sent to different multicast groups.

Note: The ip multicast multipath command load splits the traffic and does not load balance the traffic. Traffic from a source will use only one path, even if the traffic far outweighs traffic from other sources.

In Cisco IOS Software Release 12.2(53)SG, the ip multicast multipath command can be used with the s-g-hash and next-hop-based keywords to enable ECMP multicast load splitting based on source, group, and next-hop address. The next-hop-based keyword enables a more complex hash, the next-hop-based S-G-hash algorithm, which is based on source, group, and next-hop address. The next-hop-based S-G-hash algorithm is predictable because no randomization is used in calculating the hash value. Unlike the S-hash and basic S-G-hash algorithms, the hash mechanism used by the next-hop-based S-G-hash algorithm is not subject to polarization.

The LAN base image is supported on the Supervisor II-Plus-10GE and the Supervisor 6L-E only. It is primarily focused on customer Layer 2 requirements containing basic access layer functionality. Release 12.2(53)SG adds the following features to the LAN Base image to meet the continuing access requirements of today's customers.

Table 3. List of features added to LAN Base package in 12.2(53)SG

Feature Name

Description

EnergyWise

EnergyWise is an innovative energy management architecture that is available to the entire Cisco Catalyst switching portfolio.

Rapid Per Vlan Spanning Tree (RPVST+)

Rapid PVST+ is an updated implementation of STP that allows you to create one spanning tree topology for each VLAN.

Smartports

SmartPorts is a cross-Catalyst solution that simplifies the configuration of critical features for Ethernet networks. SmartPorts makes available configuration best practices with pre-tested, Cisco-recommended, switch port configurations or "templates".

AutoQoS

AutoQoS dramatically simplifies QoS deployment by automating QoS features for voice traffic in a consistent manner and leveraging the advanced functionality and intelligence of Cisco IOS Software.

Enhanced Power over Ethernet

Cisco Enhanced PoE is Cisco's extension to the IEEE 802.3af standard that delivers up to 20W per port.

Multicast Listener Discovery (MLD) Snooping

Enable efficient distribution of IP version 6 (IPv6) multicast data to clients and routers in a switched network.

Flexlink+

Allows users to configure a Flex Link pair to allow both ports to forward the traffic for a set of VLANs which are mutually exclusive.

This release provides hardware support for Supervisor Engine 6L-E and software support for OSPF for routed access, IP multicast load splitting with ECMP and some repackaging of features from the IP Base image to the LAN Base image.